Internet Protocol Television (hereinafter, IPTV) is exploring the delivery of encoded content using Multiview Video Coding (hereinafter, MVC) in which 3D video is multiplexed such that a left-view video serves as a base view and a right-view video serves as a dependent view. The MVC scheme has the base view serve as both the left-view video and as a 2D video, such that 2D video playback is possible by extracting the base view alone. Patent Literature 1 discloses technology for embedding, within a stream, control information that indicates a period in which switching a viewing mode between 2D and 3D is possible, thus enabling a switch between viewing modes during the period.
When a piece of content is playable in either of a 3D viewing mode and a 2D viewing mode, the user may plausibly decide to switch from one viewing mode to another viewing mode, while playback is in progress. For example, a user who begins to view a piece of content in 3D using 3D glasses may wish to continue viewing in the company of a second user who does not have 3D glasses, or may begin viewing a piece of content in 2D and then wish to view subsequent visually-impressive scenes in 3D.
When the viewing mode is changed while playback is in progress, the piece of content is encoded according the aforementioned MVC scheme, and the 3D video and 2D video are similar enough to differ only in whether or not a stereoscopic effect is possible, the user is unlikely to experience discomfort when changing the viewing mode.